三氧化二砷对大鼠肺纤维化模型的干预作用及其机制的探讨

Influence of arsenic trioxide on bleomycin-induced lung fibrosis in rats and its mechanism

目的观察三氧化二砷(arsenictrioxide,AS2O3)对博莱霉素-A5(bleomycin-A5,BLM-A5)所致大鼠肺纤维化有无治疗作用并探讨其作用机制。方法50只SD大鼠分为空白对照组、肺纤维化模型组和三氧化二砷治疗组。其中对照组10只,气管内给予生理盐水后,连续7天腹腔内注入生理盐水;模型组20只,气管内给予BLM-A5后,连续7天腹腔内注入生理盐水;治疗组20只,气管内给予BLM-A5后连续7天腹腔内注入AS2O3。每组再随机均分成2个亚组,分别于实验第7天、第28天处死。检测以下项目:①支气管肺泡灌洗液(bronchoalveolarlavagefluid,BALF)经流式细胞仪行细胞分类和炎性细胞凋亡率检测;②ELISA法检测BALF中细胞因子γ-干扰素(interferon-gamma,IFN-γ)的含量。③光镜下观察肺组织肺泡炎和肺纤维化程度;④实验第28天肺组织羟脯氨酸(hydroxyproline,HYP)含量的测定。结果与模型组相比,治疗组:①BALF中中性粒细胞和淋巴细胞百分比总和降低(P<0.05);炎性细胞凋亡率增加(P<0.05);实验第7天组IFN-γ含量降低(P<0.05)。②肺组织炎症和纤维化程度减轻;HYP含量降低(P<0.05)。结论AS2O3能减轻BLM-A5诱导的肺纤维化大鼠肺组织炎症和纤维化程度,作用机制可能与其诱导肺内炎性细胞凋亡有关。

Objective To investigate the effect and mechanism of arsenic trioxide on bleomycininduced lung fibrosis in rats. Methods 50 Sprague-Dawley （SD） rats were divided randomly into three groups including control group （ n = 10）, bleomycin-induced lung fibrosis group （ n = 20 ） and arsenic trioxide treated group（n= 20）. Each group was again divided into two subgroups randomly, which were sacrificed on 7d and 28d respectively. Bronchoalveolar lavage fluid（BALF） was obtained and the cell differentiation, the percentage of inflammatory cells＂ apoptosis as well as the concentration of interferon-gamma were detected. HE staining was performed on the lung tissue sections to observe the extent of alveolitis and fibrosis. The hydroxyproline assays of the lung tissues of rats on 28d were also made to estimate the collagen content. Results ①Compared with model group, treated group got lower percentage of neutrophils （ P〈0.05）. ② Inflammatory cells in BALF of treated group had higher percentage of apoptosis than that in model .group （ P〈0.01）. ③Compared with model group, the concentrations of interferon-gamma in BALF reduced in treated group on 7d. ④ More severe inflammation was shown in the histological examination of the lung tissue sections of model group. However,fibrotic lesion was also observed in the lungs of treated group, but the extent was limited. ⑤Hydroxyproline analysis showed that treated group had a lower content of collagen than model group. Conclusions Arsenic trioxide may ameliorate the formation of bleomycin-induced pulmonary fibrosis, which might be related to the effect of inducing apoptosis of inflammatory cells in BALF.